There are known optical modules that include semiconductor light-emitting devices within packages (for example, refer to Japanese Unexamined Patent Application Publication No. 2009-93101 (Patent Literature 1), Japanese Unexamined Patent Application Publication No. 2007-328895 (Patent Literature 2), Japanese Unexamined Patent Application Publication No. 2007-17925 (Patent Literature 3), and Japanese Unexamined Patent Application Publication No. 2007-65600 (Patent Literature 4)).